Generative or additive manufacturing methods are, for example, laser deposition welding (LMD) or selective laser melting (SLM).
A method for the additive buildup of components by means of selective laser melting is known from EP 2 910 362 A1, for example.
To produce a component from a powder bed, for example by means of SLM, the powder bed is irradiated for example by a laser beam in accordance with the design of a corresponding CAD file.
Additive fabrication methods have proved to be particularly advantageous for complex components or components of complicated or delicate design, for example lightweight structures. Additive fabrication is particularly more advantageous owing to a particularly short chain of process steps, wherein a manufacturing or fabrication step of the corresponding component can occur directly on the basis of the CAD file.
Furthermore, additive fabrication is particularly advantageous for the development or production of prototypes which, for example for cost reasons, cannot be produced, or cannot be produced efficiently, by means of conventional subtractive or material-removing fabrication or casting methods.
At the current time, the designs of the components are limited, in particular in terms of their dimensions, by the design of the commercially available systems which in particular offer only a limited building space. Currently available SLM systems usually have fixed building space sizes. Typical dimensions for the building or manufacturing space are 250 mm×250 mm×250 mm, for example. The building space sizes can be (co-)determined, for example, by the size or area of a building platform.
At the current time, corresponding manufacturing systems are at any rate limited to a building volume of about 1000 mm×1000 mm×1000 mm. However, in particular in the case of the manufacture of long components or ones with an extent along mainly one axis, the complete building space area is not required. Consequently, a very large amount of powder has to be used for the manufacture of the corresponding component and in particular arranged or moved in the building space. Only a fraction of said powder is furthermore necessary for the actual buildup of the component. This constitutes a substantial disadvantage for the technology of additive manufacturing since the powder is not only expensive but any unnecessary (further) use of the powder can be disadvantageous for the component and also for the method. In particular, powder for each additive manufacturing process that is not processed to form the component is thermally loaded by the manufacturing conditions, for example by a laser, which can lead to an ageing process and thus to an impairment of the physical properties of the powder.
Furthermore, a large quantity of powder has to be kept in stock, for example, with it being the case that, during each (renewed) heating of the powder in the building space, the quality of the powder can be impaired by a partial oxidation and/or by the absorption of air moisture. This is particularly critical in the additive manufacturing of components for use in the hot gas path of a turbine, where even small quantities of oxygen can, for example, prevent the formation of desired or required material phases (for example the γ or γ′ phase of a nickel- or cobalt-based superalloy).